
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (* (/ (sin t_2) t_2) (/ (sin t_1) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_2}{t\_2} \cdot \frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (* (/ (sin t_2) t_2) (/ (sin t_1) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_2}{t\_2} \cdot \frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ (* (sin t_1) (/ (sin t_2) t_1)) t_2)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1 \cdot \frac{\sin t\_2}{t\_1}}{t\_2}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.8%
Final simplification97.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (* (/ (sin t_1) t_1) (/ (sin t_2) t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1}{t\_1} \cdot \frac{\sin t\_2}{t\_2}
\end{array}
\end{array}
Initial program 97.8%
Final simplification97.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* x tau) (PI))) (t_2 (* x (PI)))) (* (/ (sin t_1) t_1) (/ (sin t_2) t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(x \cdot tau\right) \cdot \mathsf{PI}\left(\right)\\
t_2 := x \cdot \mathsf{PI}\left(\right)\\
\frac{\sin t\_1}{t\_1} \cdot \frac{\sin t\_2}{t\_2}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3297.2
Applied rewrites97.2%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
lift-*.f3297.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.8
Applied rewrites97.8%
Final simplification97.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ (* (sin t_1) (sin t_2)) (* t_2 t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1 \cdot \sin t\_2}{t\_2 \cdot t\_1}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites97.7%
lift-/.f32N/A
lift-*.f32N/A
lift-/.f32N/A
lift-sin.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
associate-*l/N/A
associate-/l/N/A
lower-/.f32N/A
Applied rewrites97.7%
Final simplification97.7%
(FPCore (x tau) :precision binary32 (let* ((t_1 (sqrt (PI))) (t_2 (* (* x (PI)) tau))) (/ (* t_1 (sin t_2)) (* t_1 t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \sqrt{\mathsf{PI}\left(\right)}\\
t_2 := \left(x \cdot \mathsf{PI}\left(\right)\right) \cdot tau\\
\frac{t\_1 \cdot \sin t\_2}{t\_1 \cdot t\_2}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
associate-/r*N/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-/r*N/A
lift-/.f32N/A
frac-timesN/A
lower-/.f32N/A
Applied rewrites96.9%
Taylor expanded in x around 0
lower-sqrt.f32N/A
lower-PI.f3272.9
Applied rewrites72.9%
Final simplification72.9%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ (* t_1 (/ (sin t_2) t_1)) t_2)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{t\_1 \cdot \frac{\sin t\_2}{t\_1}}{t\_2}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.8%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3272.9
Applied rewrites72.9%
Final simplification72.9%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI)))) (/ (* (/ 1.0 tau) (sin (* t_1 tau))) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
\frac{\frac{1}{tau} \cdot \sin \left(t\_1 \cdot tau\right)}{t\_1}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites97.7%
Taylor expanded in x around 0
lower-/.f3272.7
Applied rewrites72.7%
Final simplification72.7%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI)))) (/ (sin t_1) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
\frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites97.7%
Taylor expanded in tau around 0
lower-/.f32N/A
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3266.5
Applied rewrites66.5%
Final simplification66.5%
(FPCore (x tau) :precision binary32 1.0)
float code(float x, float tau) {
return 1.0f;
}
real(4) function code(x, tau)
real(4), intent (in) :: x
real(4), intent (in) :: tau
code = 1.0e0
end function
function code(x, tau) return Float32(1.0) end
function tmp = code(x, tau) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 97.8%
Taylor expanded in x around 0
Applied rewrites65.7%
herbie shell --seed 2024327
(FPCore (x tau)
:name "Lanczos kernel"
:precision binary32
:pre (and (and (<= 1e-5 x) (<= x 1.0)) (and (<= 1.0 tau) (<= tau 5.0)))
(* (/ (sin (* (* x (PI)) tau)) (* (* x (PI)) tau)) (/ (sin (* x (PI))) (* x (PI)))))